“Speak to Bnei Yisrael and say to them: any man whose wife shall go astray and commit treachery against him…” – Bamidbar 5:12
The Torah describes the details of a sotah. If a woman acts in a manner that causes her husband to suspect her of infidelity, he should warn her not to go into seclusion with that other man. If she violates this warning, then the husband is to take her to the kohen. The kohen will give her the “bitter waters” to drink. If she was unfaithful, she will instantly die. If she was not unfaithful, she will be redeemed and blessed.
When the Torah lays out the details, it uses an unusual expression: “If a man will tishteh his wife.” The word tishteh comes from the root shoteh, which means insanity. It’s as if to say, “If a man will accuse his wife of insanity.”
Rashi is troubled by the use of this expression. He explains, based on the Gemara, that adulterers do not sin until a wave of insanity enters them. The Siftei Chachmim explains this to mean, “until their yetzer hara teaches them it is permitted.”
It seems clear from the Siftei Chachaim that the modus operandi of the yetzer hara is to convince potential sinners that the act tempting them is permitted. Only when it succeeds, and they are convinced, will they then transgress.
This statement – people only sin when they are convinced it is permitted – seems difficult to understand. If we are dealing with a pious, proper Jewish woman who got into a bad situation, she knows the act she wants to commit is forbidden. How can the yetzer hara teach her it is permitted? On the other hand, the Torah may be speaking about the opposite extreme – a woman who has gone off the path and just doesn’t care. Why does she need the yetzer hara to tell her it is permitted? She doesn’t care.
So on both sides of the spectrum, the yetzer hara either should be unable to convince the person it is permitted – or it shouldn’t need to do any convincing.
The answer to this question is based on understanding one of the most consistent quirks of human nature: “I never do anything wrong.” Whether sophisticated adults or schoolchildren, Supreme Court justices or convicted felons, humans seem never to do anything wrong. Wardens will tell you their jails are filled with self-proclaimed innocent men. Thieves aren’t wrong. Murderers aren’t wrong. You won’t find a gangster proclaiming, “Yes, it is evil to murder and pillage, but what can I do? I am weak and give into my desires.” Instead, you will hear an entire belief system explaining his approach to life is actually better for society and the world.
Why can’t a man just admit it is wrong to steal but he wants to do it anyway?
The reason for this has to do with the inner working of the human. Hashem created man out of two distinct parts. One is comprised all of the drives and passions found in the animal kingdom; it is simply base instincts and desires. The other part of man is pure intellect: holy, good and giving.
Because this part of me is made up of pure intellect and wisdom, it would never allow me to sin. It sees the results too clearly. It understands that all of Hashem’s commandments are for my good and that every sin damages me. Because of this crystal clear insight, the human would not have the free will to sin. In theory, he could be tempted to sin, but he would never actually come to the act. It would be akin to sticking his hand in a fire. In theory he could do it, but it would never happen. So if Hashem created man with just these two parts, man would not have free will in a practical sense.